Topic 1.2

Topic 1.2Energy Flow

Enduring Understanding:

Energy and nutrients move within and between biotic and abiotic components of ecosystems via physical, chemical and biological processes.

Rally Table!

Rally Table Teacher reads question and provides think

time Students think about the question, write an

answer, then pass their paper clockwise to the next person at their table.

Each student writes their answer on the paper in front of them and passes the paper until their own paper comes back to them.

Question One: Name one example of a physical

process involved in energy flow.

Question Two: Name one example of a chemical

process involved in energy flow.

Question Three: Name one example of a biological

process involved in energy flow.

Producers – autotrophs Plants &

Photosynthetic bacteria

What are the various levels of a food web?

http://www.ucmp.berkeley.edu/bacteria/cyanointro.html

Define producer

What are the various levels of a food web? Consumers –

heterotrophs Herbivores – eat only

producers

Describe how consumers obtain energy and nutrients

What are the various levels of a food web? Consumers –

heterotrophs Carnivores – eat only

herbivores

Describe how consumers obtain energy and nutrients

What are the various levels of a food web? Consumers – heterotrophs

Omnivores – eat either producers or herbivores

Describe how consumers obtain energy and nutrients

What are the various levels of a food web? Consumers – heterotrophs

Saprotrophs – fungi that absorb nutrients from surrounding environment

Describe how consumers obtain energy and nutrients

What are the various levels of a food web? Detritivores & Decomposers

Detritivores eat nonliving plant and animal remains Scavengers Beetles Worms

http://izismile.com/2012/02/20/australian_giant_earthworm_9_pics.html

Describe how consumers obtain energy and nutrients

What are the various levels of a food web? Detritivores & Decomposers

Decomposers complete the food chain Fungi Bacteria

Return nutrients to soil or oceans for use by autotrophs

http://en.wikipedia.org/wiki/Soil

http://wps.aw.com/bc_campbell_biology_7/26/6672/1708198.cw/index.html

Describe how consumers obtain energy and nutrients

Marine Food Web In a food web,

arrows show the direction of energy flow.

For example: krill eats the phytoplankton, but the energy flows from the phytoplankton to the krill.

Students will describe the energy pathways through the different trophic levels of a food web or energy pyramid.

On average about 10 percent of net energy production at one trophic level is passed on to the next level.

How does energy flow through ecosystems?

http://www.learner.org/courses/envsci/unit/text.php?unit=4&secNum=3

Trace the flow of energy through a living system.

3 Reasons for decrease in available energy

Energy is “used up” for daily life activities.

Not all organisms that die are eaten by animals in the next trophic level.

Not all parts of an organism are eaten and digested for energy.

Trace the flow of energy through a living system.

An example of an energy pyramid:

Trace the flow of energy through a living system.

Energy Pyramid An energy pyramid

is a graphical model of energy flow in a community.

The different levels represent different groups of organisms that might compose a food chain.

http://www.learner.org/courses/essential/life/session7/closer5.html

Trace the flow of energy through a living system.

Energy Pyramid from the bottom up:

Producers — bring energy from nonliving sources into the community

http://www.learner.org/courses/essential/life/session7/closer5.html

Energy Pyramid from the bottom up:

Primary consumers — eat the producers, which makes them herbivores in most communities

http://www.learner.org/courses/essential/life/session7/closer5.html

Energy Pyramid from the bottom up:

Secondary consumers — eat the primary consumers, which makes them carnivores

http://www.learner.org/courses/essential/life/session7/closer5.html

Energy Pyramid from the bottom up:

Tertiary consumers — eat the secondary consumers

http://www.learner.org/courses/essential/life/session7/closer5.html

Energy Pyramid from the bottom up:

Quaternary consumers — eat the tertiary consumers

http://www.learner.org/courses/essential/life/session7/closer5.html

Energy Pyramid

In some food chains, there is a fourth consumer level, and rarely, a fifth.

Have you ever wondered why there are limits to the lengths of food chains?

http://www.learner.org/courses/essential/life/session7/closer5.html

10% Rule

Explain how the amount of energy available at each trophic level in an energy pyramid limits the number of organisms that each trophic level can support.

An Example of a Biomass Pyramid

http://earth.rice.edu/mtpe/bio/biosphere/topics/energy/40_biomass.html

Biomass Pyramid

http://earth.rice.edu/mtpe/bio/biosphere/topics/energy/40_biomass.html

In a “biomass pyramid“, the comparative masses of consumers and food can be represented simultaneously.

Biomass Pyramid

http://earth.rice.edu/mtpe/bio/biosphere/topics/energy/40_biomass.html

Similar to the energy pyramid, the base (producers)is much broader than the top levels.

Quaternary consumers comprise only 1/10,000th of the biomass in this ecosystem.

Biomass Pyramid

http://earth.rice.edu/mtpe/bio/biosphere/topics/energy/40_biomass.html

This is the reason that there are limits to the number of trophic levels possible in an ecosystem.

Nutrient Cycling vs. Energy Flow

Energy flow is unidirectional: approximately 10% of the available energy is passed on to the next trophic level.

Nutrient Cycling vs. Energy Flow

Nutrients cycle through the food web.

From producers to consumers to decomposers, then back to producers.

Citations http://www.ucmp.berkeley.edu/bacteria/cyanointro.html http://

website.nbm-mnb.ca/mycologywebpages/NaturalHistoryOfFungi/Saprotrophs.html

http://izismile.com/2012/02/20/australian_giant_earthworm_9_pics.html http

://education.nationalgeographic.com/education/encyclopedia/food-web/?ar_a=1

http://en.wikipedia.org/wiki/Soil http://

wps.aw.com/bc_campbell_biology_7/26/6672/1708198.cw/index.html http://www.learner.org/courses/essential/life/session7/closer5.html http://earth.rice.edu/mtpe/bio/biosphere/topics/energy/40_biomass.html olhs.cksd.wednet.edu/ http://www.learner.org/courses/envsci/unit/text.php?unit=4&secNum=3